title: Peptide-mediated disruption of calmodulin-cyclin E interactions inhibits proliferation of vascular smooth muscle cells and neointima formation.
abstract: BACKGROUND
  Cell cycle progression in vascular smooth muscle cells (VSMCs) is a therapeutic target for restenosis.
  
  
  OBJECTIVE
  Having discovered that calmodulin (CaM)-dependent cyclin E/CDK2 activity underlies Ca(2+)-sensitive G(1)-to-S phase transitions in VSMCs, we sought to explore the physiological importance of the CaM-cyclin E interaction.
  
  
  RESULTS
  A peptide based on the CaM binding sequence (CBS) of cyclin E was designed to interfere with CaM-cyclin E binding. Compared with control peptides, CBS blocked activating Thr160 phosphorylation of CDK2, decreased basal cyclin E/CDK2 activity, and eliminated Ca(2+)-sensitive cyclin E/CDK2 activity in nuclear extracts from mouse VSMCs. Nucleofection with CBS, or treatment with CBS conjugated to the HIV-1 TAT protein transduction domain to improve bioavailability, inhibited G(1)-to-S cell cycle progression in a dose-dependent manner. These effects were not observed with control peptides. TAT-CBS inhibited (3)H-thymidine incorporation in primary human aortic SMCs (HA-SMCs) in vitro, manifested greater transduction into HA-SMCs compared with endothelial cells in vitro, and limited decreased SM22α expression, neointima formation, and medial thickening without affecting collagen deposition or reendothelialization in a mouse model of carotid artery injury in vivo. The antiproliferative effects of CBS remained evident in mouse embryonic fibroblasts derived from wild-type mice but not cyclin E1/E2 double knockout mice.
  
  
  CONCLUSIONS
  A synthetic peptide designed to disrupt CaM-cyclin E binding inhibits Ca(2+)/CaM-dependent CDK2 activity, cell cycle progression, and proliferation in VSMCs and limits arterial remodeling following injury. Importantly, this effect appears to be cyclin E-dependent and may form the basis of a potentially novel therapeutic approach for restenosis.
authors.affiliation: Division of Cell and Molecular Biology, Toronto General Hospital Research Institute, 200 Elizabeth St, MaRS 3-909, Toronto, Ontario, Canada.
authors.forename: Sonya
authors.initials: S
authors.lastname: Hui
authors.forename: Jaehyun
authors.initials: J
authors.lastname: Choi
authors.forename: Syed
authors.initials: S
authors.lastname: Zaidi
authors.forename: Abdul
authors.initials: A
authors.lastname: Momen
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Steinbach
authors.forename: Al-Muktafi
authors.initials: AM
authors.lastname: Sadi
authors.forename: Kiwon
authors.initials: K
authors.lastname: Ban
authors.forename: Mansoor
authors.initials: M
authors.lastname: Husain
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D001665:Binding Sites / Q000502:physiology; D001798:Blood Proteins / Q000494:pharmacology; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D023903:Coronary Restenosis / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D019927:Cyclin E / Q000737:chemistry / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D058426:Neointima / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010455:Peptides / Q000138:chemical synthesis / Q000235:genetics / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011494:Protein Kinases / Q000378:metabolism; D016196:S Phase / Q000187:drug effects / Q000502:physiology
chemical_list: D001798:Blood Proteins; D002147:Calmodulin; D019927:Cyclin E; D010455:Peptides; D011494:Protein Kinases; C102333:histone H1 kinase; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2